Vibrator



0d 14, 1941- F. H. FLElscHER ETAL 2,259,131

I VIBRATOR Filed May 5, 1959 2 Sheets-Sheet l `Figi lg Z6 Figa.

Invehtors: Fran k H.' Fleisch er,

Wagne J. Morrill, by We. MIM

Them Attorn eg.

OC- 14, 1941- F. H. FLElscHER l- TAL 2,259,131

VIBRATOR Filed May 5, 1939 2 Sheets-Sheet 2 Inventors.- FrankH.F`|eischer`, Wayne J. Morrill,

b5 .7E/M76.

Patented ct. 14, 1941 UNITED STATES;

PATENT .OFFICE vmnn'roa Frank H. Fleischer an d Wayne J. Morrill, FortWayne, Ind., assignors to General Electric Company, a corporation of NewYorkf Application Mays, 1939, serial No. 271,948

1 Claim.

The present invention relates to electromagnetic vibrators for producingan oscillating or. reciprocating movement such as may be used foroperating electric shavers and the like.

'I'he object of our linvention is to provide an improved constructionand arrangement in vibrators of this type, and for a consideration ofwhat we believe to be novel and our invention,

attention is directed to the following description and the claimappended thereto. l

In the accompanying drawings-Fig. 1 1s a top plan view of a shaverequipped with a vibrator embodying our invention, the upper half of the.casing being removed; Fig. 2 is a sectional view taken on line 2-2 ofFig. 1; Fig. 3 is a sectional view taken on line 3 3 of Fig. 2; Fig. 4is a per- I is a cutter 6 which is reciprocated by an operating lever 1having a rounded end 8 fitting in a notch 9 in the cutter. It should benoted that the operating lever is connected to one end of the cutter.This reduces sliding of the rounded end 8 in the notch 9 as theoperating lever is oscillated, thereby reducing wear and friction Thisis due to the fact that the motion losses. of the operating lever isalmost wholly in the direction of movement of the cutter. Theconstruction of the cutter and shearing head form no part' of th`epresent invention. Current is supplied to the vibrator by a conductorcord I led in through an opening II in the opposite end of the casing.

The vibrator has a'U-shaped framev I2 having exposed longitudinallyextending arms -I3' and I4 fixed together by cross braces I5 and, I6having projections I1 and I8 which project through openings in the armsI3 and I4 and are ,riveted over the outer surfaces of the arms. Thisprovides a rigid frame construction in which the arms are clampedagainst the ends ,I9 and 20 ,of the braces I and I6. Between the arms I3and I4 and extending transversely or crosswise thereof is anelectromagnet having*l a core 2| vprovided'with projections 22 and 23 atopposite ends which fit in openings 24 and 25 in the 30 between theframe arms.

a plurality of laminations which extend perpendicular to the, arms I3and I4 of the frame. The laminations are in general H-shaped, the legsof the H projecting outward from opposite sides 5 of the core adjacentthe inner side of the arms I3 and I4 to provide pairs of spaced polepieces 26 and 26a and 2'I and-21a. The active faces of each pair of polepieces are the inner or opposed faces which provide a recess forreceiving an armature. The electromagnet is energized by a coil 28 onthe core 2| and connected to the conductor cord I0 which is led alongthe under side of the frame arm I4 in a groove Illa in the casing. Theconductor cord is held adjacent the. l5 frame arm I4 by a clip IIlbthereon. The pole pieces 2G and 21 have a polarity opposite that of thepole pieces 26a and 21a. When the coil is energized from a `source ofalternating or pulsating current, the ux at the pole pieces uctuates inmagnitude in accordance with the variations in current owing through thecoil.

Fixed to the end of the frame I2 adjacent the shaving head is a U-shapedstrip spring 29 having its central portion xed by screws 3|) to the endof the frame and having spring arms 3| and 32 extending along oppositesides of the frame.`

The arms 3| and 32 are perpendicular to the frame arms I 3 and I4 andextend along the edges thereof so as to substantially enclose the spaceFixed to the spring arms 3| and 32 are armatures 33 and 34v arranged inthe recesses between the inner or opposed faces of the pole pieces 26and 26a and 21 faces of the pole pieces and are supported by the springarms for movement parallel to the inner faces of the pole pieces. Thespring arms bias the armatures to an outer position in which the edgesof the armatures are slightly beyond the ends of the pole pieces. As thecurrent in the coil increases, the armatures are drawn inward toward thecoil to a position in which the edges of the armatures are beneath theinner faces of the pole pieces. As the current in the coil decreases,the armatures are moved outward by the spring arms. The recessesprovided by the pole pieces provide ample space for the oscillation ofthe armature without striking the coil. 'I'he pieces. This eliminatesthe need for stops. The strength of the springs and the weight of theframe arms I3 and I4. 'I'he core 2| comprises 5s armatures are adjustedso that the natural frequency of` vibration of the armatures is tuned toa frequency slightly below twice the frequency of the current energizingthe coil. If the natural frequency of vibration of the amature wereexactly equal to twice the frequency of the energizing circuit, theamplitude of oscillation of the armaturewould be limited by the frictionload on .the operating lever 1. Inthe particular application this wouldmean that as the cutter 8 encountered heavier or stiffer hair, theamplitude of movement of the cutter would decrease and mightevendecrease to suclan extent as to prevent satisfactory cutting. By havingthe natural frequency of the armature slightly below twice the frequencyof the current supply the amplitude of oscillation actually increases asthe loadon the cutter increases. This eliminates any possibility ofunsatisfactory cutting due to a decrease of the cutter amplitude as thecutter load increases. The tuning or natural frequency of oscillation ofthe armatures is adjusted by weights 35 and 36 on the free ends of thearmatures. The weights project beyond the, end of the frame and, duringoscillation, move between the frame arms kI3 and i4. The armaturesvibrate in synchronism with the pulsations of the current. Sucharmatures are known in the art y as the vibrating reed type. Since thearmatures move in opposite directions, the reaction forces transmittedfrom the spring arms 3| and 32 to the frame are neutralized. The end ofthe armature 34 opposite the endunder the inuence of pole pieces 21 and21a isfixed to the operating lever 1. Since the spring arm 32 in eectsupports the armature 34 for pivotal movement about a point adjacent theportion of the spring 23 connecting the arms 3l and 32, the armature issupported intermediate its ends. This has the advantage of applyinggreater leverage to the operating lever 1. Y

In use, the vibrator is supplied from a source of alternating orpulsating current oi' the proper frequency. As' described above, thiscauses a synchronous vibration of the armatures 3,3 and 34. Thevibration of the amature 34 is transmitted to the operating lever 1. Thevibration of`the armature 33, being equal and-opposite to that ofarmature 3l, neutralizes the reaction forces'on the frame of amature 34and accordingly prevents vibration. of the shaver casing.

What we claim as new and desire to secure by Letters Patent in theUnited States is:

In an electromagnetic vibrator, a frame having spaced longitudinallyextending arms, an electromagnet having an H-shaped core extendingcrosswise of said arms and fixed at each end to the adjacent arm,` thearmsv of said core providing pairs of spaced pole pieces on oppositesides of the electromagnet, a coil on the central` part of the core,longitudinally extending spring arms xed to one end of the frame andextending toward the electromagnet, armatures xed to the spring arms andsupported `thereby'for pivotal movement about a point yadjacent thepoint of attachment of the spring arms toward and away from a positionVbridging said pole pieces, said armatures extending beyond theelectromagnet and having balance weights on the free ends, and anoperating lever xed to one of vsaid armaturesl and extending away vfromthe electromagnet and beyond -the pivot point of the armature.

f f FRANK H. FLEISCHER.

WAYNE J. MORRILL.

